JP2015121290A - Power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power transmission device which prevents a liquid packing from protruding to the exterior.SOLUTION: A power transmission device 1 transmits power and includes: a drive pinion gear 11; a ring gear 21 which engages with the drive pinion gear 11; and a case 40 which stores the drive pinion gear 11 and the ring gear 21. The case 40 is formed by mating a first case piece 50 to a second case piece 60 through a liquid packing. The drive pinion gear 11 is rotatably held by the first case piece 50, and the ring gear 21 is rotatably held by the second case piece 60. An annular groove 56 for accumulating the liquid packing is formed over an entire periphery of at least one of a first mating surface 55 of the first case piece 50 and a second mating surface 65 of the second case piece 60.

Description

  The present invention relates to a power transmission device mounted on a straddle-type vehicle such as a motorcycle.

  Motorcycles transmit power generated by a prime mover mounted approximately at the center of the vehicle body to the rear wheels. As a method for transmitting power, a chain drive type is known in which a chain is wound around a drive sprocket that is rotated by an output shaft of a transmission and a driven sprocket that is coaxially arranged with a rear wheel. .

  In addition, some motorcycles are known to have a shaft drive type that uses a propeller shaft (propulsion shaft) without using a chain and is designed to be maintenance-free. Specifically, for example, a first bevel gear is provided on the output shaft of a transmission that changes the output of the prime mover, and a second bevel gear fixed to the front end of the propeller shaft is meshed with the first bevel gear to rotate the propeller shaft. I am letting. A drive pinion shaft is splined to the rear end of the propeller shaft, and the drive pinion gear is engaged with a ring gear that is integral with the rear wheel (see Patent Document 1).

  The drive pinion shaft is rotatably held on the first case piece (first half) via the first bearing, and the ring gear shaft to which the ring gear is fixed is connected to the second case piece (second half) via the second bearing. ). The first case piece and the second case piece are fastened to each other by bolts.

JP 2008-244101 A

  By the way, in a case configured by combining the first case piece and the second case piece, oil for lubricating the drive pinion gear and the ring gear is sealed. Therefore, it is necessary to seal the mating surfaces of the first case piece and the second case piece in order to prevent the oil from leaking to the outside and to prevent intrusion of muddy water and dust into the case from the outside.

  Further, it is necessary to appropriately combine the first case piece and the second case piece so that the meshing positions of the drive pinion gear and the ring gear are appropriate. In addition, when the meshing positions of the drive pinion gear and the ring gear are shifted, abnormal noise is generated and durability may be reduced.

  Therefore, a method of interposing a thin-film liquid packing (liquid gasket) between the first case piece and the second case piece is conceivable.

  However, the liquid packing may protrude from the mating surface of the first case piece and the second case piece to the outside. And if it protrudes, it is necessary to wipe off the protruding liquid packing as well as deteriorating the beauty.

  Then, this invention makes it a subject to provide the power transmission device which prevents the liquid packing from protruding outside.

  As means for solving the problems, the present invention provides a power transmission device for transmitting power, the first bevel gear, the second bevel gear meshing with the first bevel gear, and the first bevel gear. And a case accommodating the second bevel gear, wherein the case is configured by combining a first case piece and a second case piece via a liquid packing, The second bevel gear is rotatably held by one case piece, the second bevel gear is rotatably held by the second case piece, and the first mating surface of the first case piece and the second mating surface of the second case piece. An annular recess for storing the liquid packing is formed over at least one of the power transmission devices.

  According to such a configuration, an annular recess for storing the liquid packing is formed over the entire circumference on at least one of the first mating surface of the first case piece and the second mating surface of the second case piece. When the liquid packing interposed between the first case piece and the second case piece moves on the mating surface, the liquid packing is captured and accumulated in the annular recess over the entire circumference. Thereby, it can prevent that liquid packing protrudes outside.

  In the power transmission device, it is preferable that the first case piece and the second case piece are fastened by a bolt, and the annular recess is disposed outside the bolt.

  According to such a configuration, the annular recess is disposed outside the bolt insertion hole through which the bolt is inserted. Therefore, when the bolt is fastened, the liquid recess that is about to protrude to the outside is good at the annular recess. Can capture.

In the power transmission device, the annular recess is preferably a groove.
In the power transmission device, it is preferable that the annular recess is a stepped portion that is recessed at least in one step and is open to the outside.

  ADVANTAGE OF THE INVENTION According to this invention, the power transmission device which prevents the protrusion of the liquid packing to the exterior can be provided.

It is an external appearance perspective view of the power transmission device concerning this embodiment. It is a plane sectional view of the power transmission device concerning this embodiment, and corresponds to the X2-X2 line section of Drawing 4. The plane sectional view of the power transmission device concerning this embodiment is expanded. It is a side view of the 1st case piece which concerns on this embodiment, and respond | corresponds to the X1-X1 line cross section of FIG. The plane sectional view of the power transmission device concerning this embodiment is expanded.

  An embodiment of the present invention will be described with reference to FIGS.

≪Power transmission device configuration≫
The power transmission device 1 according to this embodiment is mounted on a shaft drive type motorcycle (saddle type vehicle). However, the straddle-type vehicle may be, for example, an automatic tricycle.

  The motorcycle transmits a prime mover and a transmission (not shown) mounted in the center of the vehicle body 200, a propeller shaft 110 extending in the front-rear direction, and power from the propeller shaft 110 to the rear wheel 150 by deflecting approximately 90 °. And a power transmission device 1. The transmission shifts the power generated by the prime mover.

  The propeller shaft 110 is rotatably provided in the cylindrical swing arm 120. The front end of the propeller shaft 110 is connected to an output shaft of a transmission (not shown), and the rear end is connected to a drive pinion shaft 10 described later. The swing arm 120 is swingably attached around a pivot shaft 121 extending in the left-right direction.

≪Power transmission device configuration≫
The power transmission device 1 will be described with reference to FIGS.
The power transmission device 1 includes a drive pinion shaft 10 that rotates about an axis O1, a ring gear 21 (second bevel gear) that rotates about an axis O2, a ring gear shaft 30, a case 40 that accommodates these, a liquid, Packing (not shown). In the case 40, lubricating oil for lubricating the drive pinion gear 11, the ring gear 21, the bearing 12, and the like is enclosed.

<Drive pinion shaft>
The drive pinion shaft 10 is a cylindrical shaft extending in the front-rear direction.
A spline hole 15 is formed in the inner peripheral surface of the front end portion of the drive pinion shaft 10. A spline shaft (not shown) on the propeller shaft 110 side is inserted into the spline hole 15. And the propeller shaft 110 and the drive pinion shaft 10 rotate integrally.

  On the rear side of the drive pinion shaft 10, a frustoconical drive pinion gear 11 (first bevel gear) that is a bevel gear is formed. However, the drive pinion gear 11 may be a separate component. The drive pinion gear 11 is composed of a spiral bevel gear and meshes with the ring gear 21. That is, the drive pinion gear 11 and the ring gear 21 constitute a final reduction mechanism.

  An intermediate portion of the drive pinion shaft 10 is rotatably accommodated in a cylindrical portion 51 described later via a bearing 12.

  The bearing 12 is a radial ball bearing in which balls (rollers) are arranged in two stages in the axial direction. The bearing 12 includes a front first inner ring 12a externally fitted to the intermediate part, a rear second inner ring 12b externally fitted to the intermediate part, and one outer ring 12c internally fitted to a cylindrical part 51 described later. And a front first ball 12d and a rear second ball 12e provided between the first inner ring 12a and the outer ring 12c.

  The second inner ring 12b is in contact with the tooth back surface (front surface) of the drive pinion gear 11. An annular shim 12f for adjusting the position of the drive pinion gear 11 is provided between the outer ring 12c and the cylindrical portion 51 in the front-rear direction.

  A ring-shaped nut 13 that contacts the front surface of the bearing 12 and prevents the bearing 12 from falling off is attached to the cylindrical portion 51 in front of the bearing 12. An oil seal 14 is provided on the front side of the nut 13.

  A cylindrical boss 16 is inserted in the rear end portion of the drive pinion shaft 10. The boss 16 is rotatably supported by the cylindrical portion 51 via a bearing 17 (needle roller bearing).

  In this way, the drive pinion shaft 10 is rotatably supported by the cylindrical portion 51 of the first case piece 50 via the bearing 12 and the bearing 17.

<Ring gear, ring gear shaft>
The ring gear shaft 30 is a shaft that extends in the left-right direction. The small-diameter portion 33 (boss portion) having a smaller diameter than the medium-diameter portion 32 is provided.

  The large-diameter portion 31 is rotatably supported by a second case piece 60 described later via two bearings 34 and 34 (radial ball bearings). Therefore, the ring gear 21 is rotatably supported by the second case piece 60 described later via the two bearings 34 and 34.

  The left side of the large diameter portion 31 is partially enlarged to form a shoulder portion 31a. An annular shim 31 b that adjusts the axial position of the ring gear 21 is provided between the shoulder portion 31 a and the bearing 34.

  A hub 35 is fixed to the right surface of the large diameter portion 31 with a bolt 35a. The hub 35 is a portion with which the wheel 151 (see FIG. 1) of the rear wheel 150 abuts.

  A spline shaft portion 32 a is formed on the outer peripheral surface of the medium diameter portion 32. The spline shaft portion 32 a is splined to the spline hole 22 of the ring gear 21. Thereby, the ring gear 21 and the medium diameter part 32 (ring gear shaft 30) rotate integrally. The ring gear 21 is positioned in the axial direction by welding to the medium diameter portion 32 or by caulking the left end portion of the spline shaft portion 32a.

  The ring gear 21 is a bevel gear having a truncated cone shape, is configured by a spiral bevel gear, and meshes with the drive pinion gear 11. Further, the ring gear 21 is in contact with the left surface of the large diameter portion 31.

  The small diameter portion 33 is rotatably supported by a shell-like portion 52 described later via a bearing 36 (radial ball bearing). Specifically, the left end of the small-diameter portion 33 is reduced in steps to form a reduced-diameter portion 33a, and the bearing 36 is externally fitted to the reduced-diameter portion 33a. An annular shim 33 b for adjusting the position of the ring gear 21 is provided between the inner ring of the bearing 36 and the small diameter portion 33 in the left-right direction.

  An annular nut 37 detachably attached to the shell-like portion 52 is in contact with the outer ring of the bearing 36 so that the bearing 36 does not fall off from the shell-like portion 52. Further, a disc-shaped cap 38 is detachably attached to the shell-like portion 52 on the left side of the nut 37.

<Case>
The case 40 is a shell-like case that houses the drive pinion shaft 10 and the like therein. The case 40 has a two-part configuration in this embodiment, and includes a first case piece 50 on the left side and a second case piece 60 on the right side. The first case piece 50 and the second case piece 60 are fastened by a plurality of (here, eight) bolts 71. In the present embodiment, the first case piece 50 and the second case piece 60 are made of metal such as an aluminum alloy, and are die-cast products (cast products).

<Case-first case piece>
The first case piece 50 includes a cylindrical cylindrical portion 51 that extends in the front-rear direction, and a hemispherical shell-shaped portion 52 that extends rearward from the cylindrical portion 51 and opens to the right.

  The cylindrical part 51 accommodates the drive pinion shaft 10 and rotatably holds the drive pinion shaft 10 via the bearing 12. A stud bolt 53 for fastening with the flange portion 122 of the swing arm 120 is attached to the cylindrical portion 51.

  The shell-shaped portion 52 accommodates the small-diameter portion 33 and holds the small-diameter portion 33 rotatably via the bearing 36. A lubricating oil inlet 54 is formed in the shell 52. A plug 59 (lid) is detachably attached to the inlet 54.

<Case-second case piece>
The second case piece 60 has a cylindrical shape. The second case piece 60 accommodates the large-diameter portion 31 and rotatably supports the bearings 34 and 34.

<Case-mating surface of first case piece and second case piece>
The mating surface S1 of the first case piece 50 and the second case piece 60 extends in the front-rear direction and has an annular shape (circular shape) when viewed in the axial direction (viewed in the left-right direction) (see FIG. 4).

  Specifically, the mating surface S1 includes an annular first mating surface 55 formed by an opening edge on the right side of the hemispherical shell-shaped portion 52, and an opening edge on the left side of the cylindrical second case piece 60. And an annular second mating surface 65 formed by the portion. Since the first mating surface 55 and the second mating surface 65 have the same shape when viewed in the axial direction, the first mating surface 55 will be mainly described below.

  As shown in FIG. 4, the first mating surface 55 has an annular shape when viewed in the axial direction (viewed in the left-right direction) and has a predetermined width in the radial direction. A screw hole 72 into which the bolt 71 is screwed opens at the first mating surface 55. That is, a plurality of screw holes 72 (eight in this embodiment) are opened at the first mating surface 55, and the plurality of screw holes 72 are arranged at equal intervals in the circumferential direction.

  The portion of the first mating surface 55 in which the screw hole 72 is formed projects outward in the radial direction and is wider than the other portions. The second case piece 60 is formed with a bolt hole 73 through which the bolt 71 is inserted.

<First case-annular groove>
An annular groove 56 (annular recess) is formed along the radially outer edge of the first mating surface 55 and radially outward of the screw hole 72 (see FIGS. 3 and 4). That is, the annular groove 56 is formed continuously from the radially outer edge of the first mating surface 55 over the entire circumference at a predetermined interval and surrounds the plurality of screw holes 72. In FIG. 4, for easy understanding, a pattern is given to the annular groove 56 that is recessed on the back side of the drawing.

  The annular groove 56 is formed by a projecting die formed on the die of the first case piece 50 that is a die-cast product. That is, the annular groove 56 is formed without using machining such as cutting.

  The annular groove 56 is a storage part that captures the liquid (silicone-based sealing material) constituting the liquid packing and stores the liquid in the inside. The liquid packing tends to protrude outside the case 40 when the first case piece 50 and the second case piece 60 are fastened with the bolts 71.

<Liquid packing>
The liquid packing is a thin film layer that seals the mating surface S <b> 1 of the case 40. The liquid packing is a thin film formed by applying a silicone sealant (packing liquid) to at least one of the first mating surface 55 and the second mating surface 65 and sandwiching it between the first mating surface 55 and the second mating surface 65. Formed in a shape.

  In this case, even if a slightly larger amount of packing liquid is applied to spread the entire surface of the mating surface S1, the packing liquid (liquid packing) that tends to protrude to the outside when tightened is annular. It is captured and stored in the groove 56. That is, the packing liquid (liquid packing) does not protrude to the outside, and it is not necessary to wipe off the packing liquid.

≪Function and effect of power transmission device≫
The effect of the power transmission device 1 will be described.
Since the first case piece 50 and the second case piece 60 are fastened with the bolt 71 in a state where the thin film-like liquid packing is sandwiched on the mating surface S1, the first case piece 50 and the second case piece 60 The relative positional relationship is kept good.

  That is, the drive pinion shaft 10 is held by the first case piece 50 and the ring gear 21 is held by the second case piece 60, but the first case piece 50 and the second case piece 60 are combined at a predetermined position. Therefore, the meshing position between the drive pinion gear 11 and the ring gear 21 is kept good. That is, the drive pinion gear 11 and the ring gear 21 that are meshed with each other are held in separate cases, but the first case piece 50 and the second case piece 60 are excellently affected by the thickness of the liquid packing. Therefore, the drive pinion gear 11 and the ring gear 21 mesh well.

  In this way, the meshing positions of the drive pinion gear 11 and the ring gear 21 are easily maintained properly. Therefore, the durability of the drive pinion gear 11 and the ring gear 21 is enhanced.

  Further, since the annular groove 56 is disposed on the outer side in the radial direction than the screw hole 72 (bolt 71), the packing liquid that tends to protrude to the outside when the bolt 71 is fastened can be captured well.

≪Modification≫
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to this, For example, you may change as follows.

  In the above-described embodiment, the configuration in which the annular groove 56 is formed on the first mating surface 55 is illustrated. However, for example, instead of or in addition to the annular groove 56, the annular groove is also formed on the second mating surface 65. It may also be configured. In this case, the annular groove 56 of the first mating surface 55 and the annular groove of the second mating surface 65 may be formed so as to be shifted in the radial direction. In addition, the annular groove 56 may be formed in the first mating surface 55 with two or more layers.

  As shown in FIG. 5, it is good also as a structure provided with the cyclic | annular level | step-difference part 57 (annular recessed part) instead of the annular groove 56 (refer FIG. 3, FIG. 4). The annular stepped portion 57 is formed by denting the outer peripheral edge of the first mating surface 55 to the left with a step difference. That is, the annular stepped portion 57 is formed over the entire circumference of the first mating surface 55, and its radially outer side is open to the outside. According to the annular stepped portion 57 like this, like the annular groove 56, it is possible to capture and store the liquid packing that is about to protrude outside.

  In the above-described embodiment, the power transmission device 1 is exemplified as a structure mounted on a motorcycle (saddle-type vehicle). It may be applied to a reduction gear.

DESCRIPTION OF SYMBOLS 1 Power transmission device 10 Drive pinion shaft 11 Drive pinion gear (1st bevel gear)
12, 34, 36 Bearing 21 Ring gear (second bevel gear)
30 ring gear shaft 40 case 50 first case piece 55 first mating surface 56 annular groove (annular recess)
57 annular step portion 60 second case piece 65 second mating surface 71 bolt S1 mating surface

Claims (4)

A power transmission device for transmitting power,
A first bevel gear;
A second bevel gear meshing with the first bevel gear;
A case housing the first bevel gear and the second bevel gear;
With
The case is configured by combining a first case piece and a second case piece via a liquid packing,
The first bevel gear is rotatably held by the first case piece;
The second bevel gear is rotatably held by the second case piece,
At least one of the first mating surface of the first case piece and the second mating surface of the second case piece is formed with an annular recess for storing the liquid packing over the entire circumference. Transmission device. The first case piece and the second case piece are fastened with bolts,
The power transmission device according to claim 1, wherein the annular recess is disposed outside the bolt. The power transmission device according to claim 1, wherein the annular recess is a groove. 3. The power transmission device according to claim 1, wherein the annular recess is a stepped portion in which at least one of the annular recesses is recessed at a step and is open to the outside.

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